LEDs blink from acoustical energy transfer across the room

Speakers are pretty inefficient at turning electrical signals into sound (and vice versa), so there was significant sound energy in the room to make the LEDs light up. I had the amp turned up to near clipping and you can hear about everything in the room vibrating.

Category:

Science & Technology

Tags:

• light
• emitting
• diode

[CoolDudeClem]

Were the speakers used to play the music powered with the little monoblock amp? I think if you did a freqency sweep the leds show what freqeuncy each speaker is most responsive to.

[vegmatic1966]

@CoolDudeClem I used "Little Oakie" the stereo amp I built into the Oak case last Summer. It uses the same TDA2050 ICs as the monoblock. It is probably more of a room response as the speakers are designed to have a flat response. You might have noticed how certain frequencies build up in different parts of your room when playing bass notes.

[SSKhay]

i think its a little bit of induction ... acoustic energy is being transformed by the speakers into electrical energy using the coil and magnet ... now the amount of energy is dictated by how hard is the rubber membrane of the speaker ... the same principle is applied by microphones

[FussyCashew]

You should try that with pezios, probably much better results. Just a theory though.

[tadgesualdo]

It looked as if engergy was being stored in the coil of the VC until it reached the threshold of the LED then the LED discharged it. Either that or there was some acoustic content that I could not hear on my tiny computer speakers that was less frequent than what I could hear. I make chokes that store engergy in ferrite cores then discharge it when the current stops, in a battery desulfator I made for my lead acid batteries.